The present invention relates to processing image data in an on-line editing system.
On-line editing systems are known in which edit decisions are made with reference to the original source video material. Resulting output video, usually recorded onto videotape, then provides original material for broadcast or other purposes and therefore represents the final output product.
On-line systems are required to operate at full definition and are therefore expensive, particularly if they are to facilitate all of the creative tools available to an editor. Editing directly from video tape to create an output video tape may be referred to as linear editing, given that the time taken to locate a particular position on the video tape will be dependant upon the position of the frames physically on the tape. A recent trend has been towards non-linear editing in which video clips are digitised and stored on magnetic discs. In this way, particular video frames may be selected within a clip without having to rewind the tape such that the time taken to locate a particular clip is no longer related to its position within the overall sequence of frames.
Non-linear editing suites are known in which source material is captured and stored at a lower definition, usually using spatial compression techniques. Edit decisions are then made at this lower definition in an off-line editing process, resulting in a list of decisions being made which are written to a transport medium, such as a floppy disc, using decision list protocols. The edit decision list (or EDL) is then supplied to an on-line editing suite into which the source material is captured, this time at full resolution and an output tape is produced in response to the decisions defined in the list.
In addition to editing the source material, on-line systems often manipulate the input images, so as to define video effects etc., resulting in new source material being produced which cannot be derived from the original source material. Conventionally, therefore, once an output tape has been produced from an on-line system, the edit decision list is of no use and further operations must be performed upon the new output tape.
Recently, on-line systems have been provided with enhanced levels of functionality giving them non-linear access in a way substantially similar to that provided in off-line suites. It would therefore be desirable to allow output tapes to be viewed and, if necessary, to be re-manipulated within the on-line suite, preferably with reference to an edit decision list. However, as previously stated, the video information is often changed such that the original edit decision list is of no use.
According to a first aspect of the present invention, there is provided an on-line editing system comprising means for conforming frames of image data from source material in response to an edit decision list; means for modifying some of said image data; means for producing an output tape including said modified frames; and means for producing an output edit decision list with conventional editing references to said output tape and with references encoded as comments to the original source material.
In a preferred embodiment, the means for producing an output edit decision list includes means for writing said data to a data carrying medium. Preferably, said data carrying medium is a transportable magnetic disk.
Preferably, the means for producing an output edit decision list includes means for encoding said references as comments.
According to a second aspect of the present invention, there is provided a method of on-line editing video material, comprising steps of conforming frames of image data from source material in response to an edit decision list; modifying some of said input data; producing a video output including said modified frames; and producing an output edit decision list with conventional editing references to said video output and with encoded references to the original source material.
In a preferred embodiment, the encoded references are encoded as comments.
According to a third aspect of the present invention, there is provided a data conveying media having data encoded thereon representing an edit decision list having conventional references to edited video material and encoded references to source video material.
In a preferred embodiment, the conveying media is fabricated in the form of a magnetic disk and said magnetic disk may be transportable between machines. Preferably, the conventional references are created within a full bandwidth editing suite and said encoded references refer to edits performed by a previous editing operation using a reduced bandwidth editing suite. Preferably, the encoded references include capture hints for capturing source material.